Here's what led up to the shooting, according to witnesses and Chief Alexander.

At about 1 p.m., a man saw someone getting mugged in the parking lot of the Hairston Village Shopping Center at Memorial Drive and North Hairston Road.

The man intervened and stopped the mugging, but the man and the mugger ended up fighting each other.

They were fighting just outside the entrance to the Kroger.

The mugger pulled out a gun and started shooting. He fired several rounds. He shot in the direction of the man's car, which was parked next to the entrance. The man's wife and 2-year-old son were in the car, and their son was shot at least once in the stomach.

The gunman got away.

Someone carried the boy into the Kroger and placed him on top of one of the check-out counters.

A pharmacist gave first aid while the ambulance was on the way.

The boy was taken to the hospital.

Kroger customers heard the shots. Some dropped to the floor. A store manager asked everyone to go to the rear of the store for safety.

"All of a sudden, we heard pow, pow, pow, pow, pow, pow. About five or six shots," said one customer, Evelyn Hearns of Stone Mountain. "And you seen them open the back door [of the car] and bring out this baby, and they laid him across the registers [inside the supermarket]. And that's when the mama, she was just hysterical."

She said store employees helped customers to the back of the store, and they were locked inside the store until police arrived.

"It was so scary," said Betty Sheferaw. "Everybody just kind of bent down on the ground."

"I just fell out on the floor," said a man as he was leaving the store.

When police arrived they roped off the parking lot and began interviewing witnesses and collecting evidence. K-9 officers walked their dogs through the parking lot trying to pick up the gunman's scent.

Chief Alexander said investigators hoped the store's surveillance cameras recorded clear video of the gunman, to help them identify and catch him.

The man's car was riddled with bullets, and the windows were shot out.

At about 5:30 p.m. police towed away the car and allowed Kroger to re-open.

Chief Alexander praised the man who intervened, calling him a Good Samaritan.

"We had a Good Samaritan who got himself involved in trying to help someone else," Alexander said.

Alexander did not yet have details of the initial confrontation, when the man first spotted what he believed to be a robbery in progress in the shopping center parking lot.

He said the man successfully stopped that mugging, saving the victim.

The initial confrontation was at one end of the expansive parking lot, near Memorial Drive.

But the Kroger is at the far end of the parking lot, and Alexander said he was not sure, yet, how the two men ended up there for the second confrontation that ended with the gunfire.

"This is such a sad and tragic incident here today, it's just horrible," Alexander said.

He talked, briefly, with the man.

"He appears to be just a real, very soft-spoken, very kind man, and very tearful, right now, as well, too."

And, the Chief said, he was unarmed.

"This was just a very good man who was trying to help someone else, but our prayers are with this child and with the family."